moavoy



May 26, 1931. D. J. M AVOY 1,807,578

' SAND DISPLACER Filed Dec. 29, 1928 2 Sheets-Sheet 2 Patented May 26, 1931 UNITED STATES PATENT? OFFICE DAN J. MCAVOY, OF CLEVELAND, OHIO, ASSIGNOR TO THE GRABLER MANUFACTURING COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO SAND DISPLAGER Application filed December 29, 1928. Serial No. 329,242.

This invention relates to molds and particularly to sand displacers for molds used with molding machines of the type described in U. S. Patent No. 1,666,577 granted April 17 1928, the invention being especially useful in making relatively large molds and particularly those for casting relatively large cylindrical pieces.

In the type of molding'machine described in Patent 1,666,577 above referred to the molds are formed with the impression of the part to be molded on each side so that on stacking one on another a number of like molds are produced. In the arrangement described in the patent, only one mold flask is used and the ramming head and pressure head each have a pattern, the impression of which is formed in the sand when compressed in the flask. When the patterns are comparatively large the sand is compressed very unevenly in the flask, that part of the sandbetween the parts of the pattern being packed much harder than the sand in the outer part of the flask, producing a very-inferior mold.

The object of my invention is to provide means for displacing part of the sand in the mold flask so that when the sand is compressed between the patterns in the flask, an even distribution and packing of the same is effected.

A further object is to provide a sand displacer which may be used in a molding machine without materially decreasing the speed at which it may be operated.

placer which is simple in construction and which may be used on the sand frame already in use without materially altering the same, and which when in'place in the mold flask does not interfere with the usual manner of filling or the leveling of the sand in the flask after filling.

With these and such other objects in view as will be apparent from the description, the

5 invention resides in the novel features of con- In the accompanying drawings Fig. 1 is a side elevation of the pressure head and ram- A further object is to provide a sand dis the sand displacer in position on the sand flask and frame; Fig. 3 is an end elevation partly in section of the structure shown in Fig. 1; Fig. 4i an end elevation similar to Fig.

.3 showing sand displacer removed and the parts in the compressed position; Fig. 5 is a sectional elevation of the mold when finished and removed from the machine; and Fig. 6 is a fragmentary detail View of a portion of the sand frame showing how the cross strips of the sand displacer are seated therein.

In the illustration of my invent-ionas shown in the accompanying drawings, 1 designates the ramming head and 2 the pressure head of a molding machine of the type described in Patent 1,666,577 above referred to. Secured to the ramming head 1 and pressure head 2 respectively are the pattern frames 3 and 4, and to these pattern frames are attached the pattern plates that carry the patterns 5 and 6.

On the pattern frame 3 and about the pattern 5 is the mold flask 7 provided with apertured ears 8. Projecting upwardly from the pattern frame are pins 9 over which the aper tured ears 8 of the flask engage for properly positioning the flask on the pattern frame.

On the top of the mold flash 7 is positioned the sand frame 10 which also has apertured ears 11 engaging over positioning pins 12 which project from the top of the mold flask.

To the upper pattern frame 4 are secured spring fingers 18 by means of screws 14:. There are also stop members 16 secured to the upper pattern frame by means of screws 15. The stop members 16 limit the distance the top pattern frame may telescope into the sand frame during the compression stroke of the ramming head. It will be noted that the lower edge to allow for displacement between the teeth of any sand that ina be present on the top edge of the sand frame, so proper spacing of the parts is always obtained.

The sand displacer is composed of a wedge shaped block 18 extending the length of the pattern and strips 19 and 20 which are secured across the top of the block. The strips 19 and 20 are received in notches 21 in the top of the sand frame 10, as shown in Fig.

6, these notches being preferably tapered to prevent sand from being lodged therein. The block 18 may be wedge shaped in cross section or any other shape which will allow it to be readily lifted out of the mold flask after the sand has been run in. The volume of the sand displacer is of course predetermined, since it must not be so large that an insuflicient amount of sand remains in the mold flask and frame when the sand displacer is removed.

The cross strips 19 and 20 of the sand displacer seat into the sand frame so that the top of the strips are flush with the top of the frame, so that the sand may be leveled by striking d the excess sand in the frame after filling in the usual manner.

In operation with the pattern frames 3 and 4 secured to the ramming head and pressure head respectively of the molding machine and with the ramming head in its lowered position as shown in Figs. 1 and 3. the mold flask is seated in place over pins 9, the sand frame placed on the mold flask over the pins 12, and the sand displacer seated in the notches 21 in the sand frame. The sand is run into the flask and any excess is scraped off flush with the top of the sand frame and bars 19 and 20 of the sand displacer in the usual way. The sand displacer is then removed and the ramming head caused to move upward until the top of the sand frame strikes the stops 17 on the upper pattern frame as shown in Fig. l. Jlhe top pattern and pat tern frame compress the sand in the mold flask leaving the top surface of the sand flush with the top of the mold flask. On this compression stroke the spring lingers 13 engage over the sand frame 10 (Fig. 4) and as the ramming head with mold flask again move downward the sand frame is held on the top pattern frame. The mold flask with sand compressed therein constituting the mold, is lifted off the pattern frame Fig. 5) and an empty mold flask put in place. The sand frame is slipped from the top pattern frame and put in place on the empty mold flask, the sand displacer put in position and the cycle of operation repeated.

lVith the cavity in the loose sand formed by the sand displacer in substantially the position the top pattern takes when the sand is compressed, a very uniform compression of the sand takes place, the sand at the sides of the mold flask being compressed substantially the same as the sand directly between the patterns. Thus a mold of good quality is produced, and each mold is the same, each con taining exactly the same amount of sand and each compressed uniformly.

Having thus described my invention, what I claim is:

1. In a molding apparatus the combination of co-operating patterns positioned one above the other and movable toward and from each other, a mold flask positioned about the lower pattern, a sand frame in alignment with and removably secured to the upper edge of said mold flask, and sand displacing means in said flask about which sand is run when the mold flask is filled, said means being removable after the mold flask and sand frame are filled, leaving a depression in the sand into which the upper pattern is pressed as the parts are moved toward each other in compressing the sand in said mold flask.

2. In a. molding apparatus the combination of cooperating patterns positioned one over the other and relatively movable toward and from each other, a mold flask positioned about the lower pattern, and sand displacing means in said flask above said pattern, means for supporting the same from the upper edge of said flask, said sand displacing means being removable and when removed. leavin a depression of predetermined. size in said sand into which the upper pattern may be pressed when the sand is compressed in said mold flask.

3. In a molding apparatus the combination of cooperating patterns positioned one over the other and movable toward and from each other, a mold flask positioned about the lower pattern, a sand displacing member positioned in said mold flask above the pattern about which the sand is run when the flask is filled, said member being smaller at the bottom than at the top whereby it is readily removed after the flask has been -fllled leaving a depression in the sand into which the upper pattern may be pressed when the patterns are moved toward each other for compressing the sand in said mold flask.

l. In a molding apparatus the combination of cooperating patterns, a mold flask positioned about one of said patterns into which sand is run and compressed by the other of said patterns, a sand frame positioned on said mold flask, and a sand displacing member of predetermined volume positioned in said mold flask above said pattern about which the sand is run, said member being shaped to permit easy withdrawal. of the same from the sand and means secured to the top of said member for supporting the same from the top of said mold flask.

5. In a molding apparatus the combination of cooperating patterns, a mold flask positioned about one of said patterns into which sand is run and compressed by the other or" said patterns and a sand displacer positioned in said mold flask above said pattern about which the sand is run, said displacer when removed leaving a hollow in the sand into which the other of said patterns is pressed on compressing the sand in said mold flask, said sand displacer comprising a member of predetermined volume and of a length substantially equal to that of the patterns, and being wider at the top than at the bottom to facilitate its withdrawal from the sand, and means secured to the top of said displacer for supporting it from the top of said mold flask.

6. An apparatus for producing molds including a base, a pattern positioned upon said base, a mold flask on said base surrounding said pattern, a block, means for positioning said block in said flask, and a second pattern having a shape somewhat different from that of said block and adapted to be pressed into said flask in a position corresponding to that of said block after the flask has been filled With sand and said block removed.

7. An apparatus for producing molds including a base, a pattern positioned upon said base, a mold flask on said base surrounding said pattern, a block, means for positioning said block in said flask, and a second pattern having a shape somewhat diiferent from that of said block and adapted to be pressed into said flask in a position corresponding to that of said block after the flask has been filled with sand and said block removed, said block being wedge-shaped and deeper than said second pattern.

8. The method of producing a mold which includes the steps of placing a flask around a pattern on a base, positioning a block in said flask, filling said flask around said pattern and block with molding sand, removing said block, and pressing a second pattern into said sand in a position corresponding to that occupied by said block.

In testimony whereof, I hereunto affix my signature.

DAN J. -MoAVOY. 

